1. The Field of the Invention
This invention relates to optical transceivers and, more specifically, to optical sub-assembly blocks that include a system for positioning and retaining components such as transmitter and receiver optical sub-assemblies in a desired position and orientation.
2. Related Technology
Fiber optic technology is increasingly employed as a method by which information can be reliably transmitted via a communications network. Networks employing fiber optic technology are known as optical communications networks, and are marked by high bandwidth and reliable, high-speed data transmission.
Optical communications networks employ optical transceivers in transmitting information via the network from one node to another. An optical transceiver operating in a network includes a transmitter that receives an electrical signal, containing digital information or other data, from a network device, such as a computer or switch, and uses an optical transmitter such as a laser to convert the electrical signal to a modulated optical signal. The optical signal can then be transmitted in an optical fiber cable via the optical communications network to a remote location. The transceiver also includes a receiver that receives an optical signal from a remote location and converts the optical signal to an electrical signal using a photodetector. These electrical signals are then sent to a host device, such as a computer or switch, for processing or further transmission in the network.
Many conventional transceivers are modular and are constructed and operate in accordance with any of a number of industry standards. The laser associated with the transmitter is typically housed in a transmitter optical sub-assembly, or TOSA. The TOSA communicates with a laser driver, a controller, and other devices on a printed circuit board (PCB) positioned in a transceiver module housing. The TOSA also connects with an optical fiber to permit the optical signals generated by the laser to be properly launched onto the optical network.
Similarly, the photodetector associated with the receiver is housed in a receiver optical sub-assembly, or ROSA. The ROSA communicates with a post-amplifier and other devices on the PCB in the module housing. The ROSA also connects with an optical fiber to permit incoming optical signals to be properly coupled into the ROSA. The housing of the transceiver module provides various functions, including mechanical stability and strength, maintenance of the proper positioning of the TOSA and ROSA, electromagnetic interference containment, electrical connection to the host device, and physical containment and protection for the TOSA, ROSA, PCB, and the devices on the PCB.
Although optical transceiver modules typically are constructed and operate according to industry standards, the mechanical details of the TOSA, ROSA, PCB, electrical connections therebetween, and the housing, often vary between devices produced by different manufacturers and between different models produced by individual manufacturers. One of the most important and difficult aspects associated with the design and construction of many optical transceiver modules concerns the stabilization of the TOSA and ROSA in a position where the TOSA and ROSA can properly connect with the optical fibers and engage in optical communication therewith.